The invention discloses a control system of a prefabricated bag packing machine and relates to the technical field of mechanical control of packing machines. The control system of the prefabricated bag packing machine comprises a feeding mechanism, a pushing mechanism, a bag stretching mechanism, a bag opening mechanism and a bag conveying mechanism and is characterized by further comprising a clamping mechanism and a translation mechanism. The control system of the prefabricated bag packing machine is applicable to packing machines for packing via prefabricated bags such as small packing machines, medium packing machines and large packing machines and the like; meanwhile, the control system of the prefabricated bag packing machine is also suitable for packing materials such as facial tissues, flat paper, paper towels, blocky foods, drugs, roll paper, unpackaged foods and the like. Through the control system of the prefabricated bag packing machine, the problems that processes in single station of the prefabricated bag packing machine are complex, various packing actions are needed, the travel distance among the stations is long, the equipment occupied area is large, the material is irregular and is easy to pour, the prefabricated bags are easy to break, the material-pushing travel distance is long, the packing effect is poor, and the packaging efficiency is low in the prior art can be solved.